Improbable
by serenelystrange
Summary: Suga Bee requested Tony and Bruce bonding over a baby or child. So, this happened. When a baby is abandoned at Tony's door, it doesn't quite turn out like he planned. But maybe that's OK. Hope you like! :-D Reviews are greatly appreciated. M for vague sexual references.


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'_Her name is Raeline. Please, Mr. Stark, please take care of her.'_

_._

Tony stares at the note-card in his hand for a moment longer, before shoving it roughly into the pocket of his jeans. When Jarvis had alerted him that a package was left outside the main door, he certainly hadn't expected this. He looks down at the baby, swathed in a fuzzy pink blanket and buckled into an infant carrier. She's looking up at him with watery eyes, and Tony does the only thing he can think of. He grabs the carrier and goes inside, yelling for Pepper before the door has even closed.

.

"Is she yours?" Pepper asks, searching the baby's face for any hint of a resemblance to Tony.

"I never cheated on you!" Tony exclaims.

They're sitting on the couch in the den, the baby between them.

Pepper sighs and shakes her head with fond exasperation.

"I believe you. But we've been separated for nearly a year now. This baby can't be more than six months old, look at her."

Tony assesses the baby carefully, but all his mind can really come up with is "tiny."

"I'm always careful," he says, instead, "She can't be mine."

"Then why would somebody leave her on your doorstep? Last time I checked, Stark Tower wasn't a hospital or a church," Pepper says, cocking an eyebrow at him.

"Banner!" Tony says suddenly, hopping to his feet and grabbing the carrier before practically running off. Pepper's left to stare after him for a confused second, before she runs to catch up.

.

"Hey," Bruce greets Tony and Pepper as they all but storm into his lab. He's wearing black trousers and a deep blue button up shirt, the sleeves rolled up to his elbows. In any other situation, Tony would take a moment to appreciate the sight of him, complete with tousled hair and sexy glasses.

Then again, Tony thinks, no moment is a bad moment to appreciate Bruce Banner in his element. But he's here on a mission, so he makes his moment brief.

"Banner," Tony says, "Looking good, love the whole 'sexy professor' look you've got going on. And hey, can you do a DNA test? Well, I mean, of course you _can_, you're a brilliant scientist, you can handle a simple DNA test. But will you?"

Bruce, used to Tony's rambling by this point, lets the words soak in as he finally notices the baby that Tony's placed on the table. He sends Pepper a questioning look, but she just shrugs and gestures to Tony.

"Is she yours?" he asks, completely ignoring the 'sexy professor' comment. Tony flirts like people breathe. Constantly and without conscious thought.

"No," Tony says with more certainty than Bruce expected, "But I want medical proof, just in case."

"You know," Pepper interrupts, "I do actually have a company to run. Do you two think you can handle this?"

"What? Yeah, go ahead," Tony says, "Schmooze, finagle, do whatever it is you do that keeps us from crashing and burning. Bruce and I can handle one little baby, right, Banner?"

Pepper looks at Bruce, who looks back at her with an uncomfortable expression on his face, but he nods.

"We'll be fine," he says, "I'll do the test, and if she's not Tony's, we'll bring her back."

"Good," Pepper says, smiling at him before turning her attention back to Tony.

"Let me know if I need to draft up some "New Daddy" announcements," she says, so sweetly that they'd almost believe she wasn't mocking him.

Almost.

"Be gone, woman!" Tony exclaims, laughing after her as she spins on her heels expertly and takes her leave.

"It's good you two still get along," Bruce says after Pepper is gone. "It'd be a really messy company if she hated you."

"Yeah, well… that's true," Tony says, shrugging. "Now, Maury me up!"

"I don't…" Bruce says, looking confused.

Tony sighs.

"You're worse than Rogers sometimes. Never mind. Let's just do this."

Bruce shakes his head, but moves over to the table anyway to get a better look at the baby. She looks up at him and makes some gibberish sounds as she struggles against her blanket and restraints.

"I think she's overheating," Bruce says, unclipping the carrier and pulling the blanket away. The baby's in a simple yellow onesie with matching socks. Immediately, she starts to wiggle at her newfound freedom and reaches her arms up a little bit in the universal 'up!' gesture.

Bruce looks at Tony expectantly, but he just stares back, unblinking.

"I don't do babies," he says, looking at her warily.

"Hold her so I can collect the samples, Stark," Bruce says, rolling his eyes, "Five minutes won't kill you."

Tony grumbles but scoops the baby up anyway, placing her against his chest so that her head rest on his shoulder. She feels foreign in his arms, and almost unbearably fragile, but she's not crying, so he counts it as a victory.

"Hey, sweetheart," Bruce says in a soft voice, making a funny face at the baby. She giggles at and Bruce takes the opportunity to swab the inside of her cheek with a q-tip.

He takes a minute to put the sample in one of his machines before grabbing another swab and going back to Tony.

"Your turn," he says, "Open up."

Tony couldn't help the smirk if he wanted to. And he really, really, doesn't.

"All you have to do is ask, Doctor," he says, grinning, before opening his mouth obediently.

"You're impossible," Bruce says, in a completely level voice that he's pretty proud of. He takes the sample and goes back to the machine.

"How long?" Tony asks, ignoring the quasi-insult.

Bruce shrugs, "With this equipment? Not very long. Now we just wait for the computer to ding."

The baby chooses that moment to speak up again, chattering in baby-speak while pushing up off of Tony's shoulder.

He readjusts her so she can sit up more comfortably on his chest and she takes advantage of the fact by grabbing Tony's nose and pulling, hard.

"Hey!" Tony says, startled. "Not cool, baby, not cool."

Once Bruce has stops laughing, he rescues Tony from the baby by taking her from him, and resting her over one hip. She snuggles into him immediately, soft brown curls hiding her face as she does.

"You know," Tony says, observationally, "She's taking this whole 'abandoned at my doorstop' thing fairly well.

"She… what?" Bruce asks. "I figured some little blonde marched in here demanding child support. Not…"

"I have Jarvis checking the footage and trying to find a match now," Tony says. "Somebody left her here, we'll figure it out."

"Poor kid," Bruce says, stroking the baby's hair soothingly. "Does she have a name?"

"Raeline," Tony replies, wrinkling his nose at the name.

"That's unfortunate," Bruce agrees, looking down at the baby in contemplation.

"How about Rae?" he suggests, "It's close enough."

"Call her whatever you want," Tony says, "She'll only be here as long as it takes for the machine to do its thing."

"Oh come on," Bruce says, moving closer to Tony. "She's adorable, don't be so scared."

Rae looks up at Tony with her sweet green eyes and gives him a toothless grin. Tony, against his better judgment, reaches out and strokes a finger down one chubby baby cheek.

"I guess she's not so bad," Tony says, finally.

Bruce grins.

.

"Who'd you knock up?" Clint asks, as he makes his way into the den to see Tony sitting on the floor with Rae lying in front of him on her back. She's chewing on some sort of teething ring that Clint assumes Pepper procured.

"Fuck off, Sparrow," Tony says, halfheartedly, flipping Clint off.

"That was just weak, man," Clint says, moving to sit across from Tony and look at Rae.

"She's cute," he says, "But really, who'd you knock up?"

"She's not mine," Tony says, "At least, like, 99% sure. Banner's running the test now. He kicked me out of the lab until it's done. Says I was 'distracting.'"

Clint snorts. "I believe it."

Before Tony can reply, Natasha appears, settling down beside Clint.

"Who'd he knock up?" she asks, giving the baby a blank stare.

Clint laughs loudly and Tony just sighs.

"Go away, both of you," he says, knowing they'll do no such thing.

Just then, Rae bursts into tears, shrieking shrilly.

"Whoa!" Natasha exclaims, moving back suddenly. "Make it stop!"

"Really?" Clint says, "Master assassin, and you're afraid of a baby?"

"Not afraid," Natasha says, crossing her arms, "But I don't know how to make it shut up without hurting it."

Clint picks Rae up protectively, rubbing her back to try and calm her down.

"I'm not going to hurt it!" Natasha says, exasperated.

Clint just stares her down until she sighs and gets to her feet.

"Whatever. I'm out. You two have fun."

She walks off, leaving Clint and Tony to appreciate the view as she goes.

"She's probably just hungry," Clint says, handing Rae back over to Tony.

"Do I look like I have breasts?" Tony asks, eyebrows nearly at his hairline.

"You don't have formula?" Clint asks, as if Tony was the idiot here.

Tony just glares, so Clint looks up at the ceiling and addresses his question to Jarvis.

"Does this house have any milk? And any chance of a baby bottle?"

"The refrigerator is stocked with milk, sir," Jarvis replies, "And I believe Ms. Potts left baby bottles and formula in the kitchen."

"There you go," Clint says to Tony, "Thanks, Jarvis."

With that, Clint stands back up and gives a half salute, before wandering off to do whatever he does when he's not shooting bad guys with arrows. Tony's not really sure.

"Ok," Tony says to Rae, whose cuddled back into his neck, clutching at his tshirt with tiny fists. "Baby bottle. I can do that. No big deal."

.

With a little help from Jarvis, Tony manages to make a suitable bottle of formula. He leans against the tall kitchen counter, and adjusts Rae so she's resting in one arm, chubby little arms holding the bottle in place as she gulps. She looks up at Tony while she's drinking, and he's struck with something that he doesn't want to name. If he's being honest, it's something akin to fondness. But Tony Stark lies best when he's lying to himself, and he pushes the thought aside.

.

Tony's never happier to be a genius engineer than a while later, when it becomes apparent that Rae needs a diaper change. A few modifications later, and one of his robots changes the diaper with impressive efficiency, replacing it with one that was tucked into the carrier. The robot rolls away and Tony picks Rae back up, just as Bruce is walking into the workshop with a sheet of paper clutched in his hand.

"What's the verdict, Doc?" Tony asks, eagerly, "Am I free to go, or do I have another 18 years on my sentence?"

Bruce shakes his head at Tony but hands over the paper anyway.

Tony reads it over, noting the lack of common chromosomes.

"I knew it!" he says, cheerfully. "I am NOT the father!"

Rae babbles at him, and Bruce can't help but think she's offended.

"Sorry, kiddo," Tony says, and for a moment, he truly looks it. It's just a flash, though, and it's gone before Bruce can comment on it.

"She's definitely not yours," Bruce agrees, smiling at Rae as she wiggles in Tony's arms. "But that doesn't really clear up why somebody left her here for you."

"Anything on that scan, Jarvis?" Tony asks.

A hologram appears in front of them, showing the footage Jarvis is analyzing. The figure placing the baby down is small, almost certainly female, but it's face is obscured by a hood and large sunglasses.

"I'm having trouble acquiring anything, sir," Jarvis admits, sounding far more disappointed than an artificial intelligence system should be able to.

"Whoever she is, she's really young," Bruce says, peering at the video.

"Why do you say that?" Tony asks. "Besides the obvious abandoning issue."

"Look at her nails," he points out, "When she puts the baby down, look at her nails. She's wearing sparkly, pink nail-polish. Most adult women would have something simpler."

Tony looks over at Bruce with surprise.

"Very astute observation, Doctor Banner. I didn't catch that."

"When will you stop with this Doctor Banner stuff?" Bruce asks, "I told you to call me Bruce months ago."

Tony beams at him.

"Never, Doctor Banner. Never. So, what's your theory on the girl, then? Teenage mom? Runaway cult member?"

"I'm not sure," Bruce says, "But it's intriguing."

"Why do I feel like I'm stuck with a baby until we solve this?" Tony asks, sighing.

The answering shine in Bruce's eyes makes babysitting a little while longer worth it.

.

Rae falls in love with Steve at dinner, a fact that amuses Bruce and makes Tony grumbly for no reason he wants to think about.

It's a rare night where they're all there, all six Avengers plus Agent Coulson. Clint's made spaghetti and garlic bread, filling the kitchen with its delicious aroma as they all sit around the massive dining table.

Rae is sitting on Steve's knee, chewing on a piece of spaghetti ineffectively, but adorably. After a while, she gives up on the pasta and focuses on gnawing on Steve's forearm instead. Steve just shrugs his shoulders and lets her.

"She must be teething," he says, "It doesn't hurt."

Tony just stares, keeping his glare to a minimum with great effort. Of course Captain America would be perfect with a baby.

"Where's she gonna sleep?" Clint asks, out of the blue. "Stark tower doesn't exactly scream 'surprise nursery'…"

Tony pauses. He hadn't considered that.

He shrugs.

"She'll stay with me. No big deal. It's only a few days, anyway. Tops."

The stunned silence from the rest of the team is awkward enough that even Thor notices it, and he speaks up.

"Have I ever told you all the tale of the flying koracran?" he asks, loud enough to draw attention to him and away from Tony.

"What's a koracran?" Steve asks, interest piqued.

"Oh, it's a terrible beast," Thor says, sagely, "It has twenty claws and breathes both fire and ice, depending on its enemy. Truly, a fearsome foe."

The team gives him their attention, and Thor tells them the rest of the tale of his fight and subsequent victory over the creature.

When the story is over, dinner is as well, and Tony practically flees with Rae to his workshop.

.

"I can do this," Tony says to himself, staring at the baby as she's lying on the table, kicking her legs.

Before he can change his mind, he unclips her onesie and removes the dirty diaper, tossing it into the nearest bin. Using two baby wipes, just in case, he cleans her off before tossing those into the bin, too. Feeling pretty proud of himself, he fastens the new diaper easily and reclips the onesie. Rae reaches for him even as he's lifting her up, and they meet halfway. Tony closes his eyes and indulges in cuddling her for a moment, smelling her sweet baby hair.

Bruce stands in the doorway, hand poised to knock, frozen by the sight before him. It's remarkably adorable and completely unbelievable at the same time.

"Hey," he says, trying not to startle them too much.

Tony's eyes snap open and meet Bruce's gaze, and he flushes slightly.

"I was just…" he says, failing at an excuse, for once.

Bruce chuckles, coming into the room and handing over Rae's blanket.

"You don't need an excuse. You're allowed to like kids. Most people do."

"I'm not most people," Tony grumbles, quietly.

"No," Bruce agrees, looking at Tony like he's seeing him for the first time. In a way, he thinks, he really is. "No, you really aren't."

Tony doesn't miss the tone in Bruce's voice, and takes a step forward, into his personal space.

"Neither are you, Doctor Banner. Goodnight."

Before Bruce can react, Tony reaches over and kisses him on the cheek, before hitching Rae a little closer and walking away.

Bruce is left standing with a tingling cheek and a head full of happy confusion.

.

.

The next day, some jerk-off with a death ray attacks Grand Central Station. When the Avengers are inevitably called to assemble, Tony finds himself arguing with Coulson.

"I can't just leave her here!" he says, as he's feeding Rae her morning bottle.

"The team needs you, Stark," Coulson says.

Tony glares, but eventually buckles under Coulson's glare.

"Fine," he says, "But you're babysitting. Don't screw up."

Coulson takes Rae with ease, resuming her feeding without batting an eye.

As soon as everyone is out of sight, he gives Rae a tiny smile and places a little kiss to her forehead.

He'll taser anyone who dares to say anything about it, anyway.

.

.

The whole day is lost to fighting and the subsequent clean up, though luckily nobody is actually killed by the death ray. In the end, Bruce hulks out and crushes the ray under one giant foot, while the others capture the bad guy. It's almost anticlimactic, but they're all so tired that they don't even care.

.

Clint, Natasha, Thor and Steve head off to a bar for a celebratory drink or ten. Tony and Bruce find Coulson in the den, fast asleep on the couch with Rae out cold on his chest.

"Quick, take pictures!" Tony whispers, reaching for his phone.

He realizes it was a bad move in the next moment, when he's lying on the floor, shaking from the electricity buzzing through him.

Coulson hasn't even opened his eyes, but he retracts the taser lines with a practiced flick and smirks.

"You probably should have expected that," Bruce says to Tony, who's busy whimpering on the floor.

Coulson stands carefully, passing the sleeping baby off to Bruce and nodding at Tony.

"He's right, you know. Frankly, I'm a little disappointed that you underestimated me."

Tony tries to growl, but it just comes out as another whimper, so he settles for glaring.

"He'll be fine in a few minutes," Coulson say, waving at them as he leaves.

.

.

When Bruce finally gets Tony back to his feet, he follows him to his room and tucks Rae into the giant bed, wrapping her blanket around her snugly.

"We should talk," he says to Tony, who looks at him with what appears to be earnest confusion.

"About what?" he whispers, leading Bruce over to the other side of the big room.

"You kissed me," Bruce says, just as quietly.

"Oh, that," Tony says, "Yeah, that was nice. You smell good, by the way."

"I… what?" Bruce says, faltering.

"You. Smell. Good." Tony says, pointedly. "And you look good. And I'm just betting you feel good, too."

Bruce can feel his flush to his toes, but instead of embarrassing him, he finds it strangely empowering.

Freeing.

"You're impossible," he says, before shoving Tony against the wall and showing him exactly how good they could feel.

Tony kisses as fiercely as he argues, and the heat of it spreads through them, until they're dizzy with it, starving for oxygen.

They stop to breathe, chests heaving, thighs slotted together to put just enough pressure to drive them crazy.

It's then, of course, that they remember the baby sleeping ten feet away.

"Fuck," Bruce gasps, dropping his head to Tony's shoulder.

"Please?" Tony says, not begging, but barely.

"Baby," Bruce reminds him, even as he goes back to sucking a mark into Tony's neck.

"Sweetheart," Tony teases, but he stops trying to unbuckle Bruce's belt.

"Later," Bruce promises, pushing back from Tony with great effort.

"I am building a fucking crib tomorrow," Tony whispers, "A whole damned nursery."

Bruce gives him a sly look. "All that for a 'few days. Tops.'?" He asks.

Tony's face is suddenly indecipherable and Bruce can practically feel him shutting down.

"Hey," he says, cupping Tony's face in his hand and forcing him to look at him. Even in the dim light of the arc reactor, Bruce can see the uncertainty and fear in his eyes.

"It's ok," he says, after running through everything he could say in his mind. "It's ok to want to keep her. And it's ok to care about her."

"What if I can't?" Tony asks, looking at Bruce with an intensity usually reserved for engineering breakthroughs.

"Care about her?" Bruce says, "That's ok, too. I mean, it's only been a couple of days and she's not…"

"Keep her," Tony interrupts, avoiding Bruce's eyes. "What if I can't keep her?"

Bruce can't help it, he grins and pulls Tony in for another kiss. It's soft and sweet and everything he didn't think either of them were capable of. But it's perfect.

"We'll figure it out," he says, "I promise. "

"Yeah?"

"Absolutely," he says against Tony's lips. "I'll smash anyone who says otherwise."

Tony laughs and pokes Bruce in the chest before resting his hands on Bruce's waist.

"You would not," he says, "You're too nice for that."

"Yeah, maybe," Bruce admits, "But they don't need to know that, do they?"

Tony grips Bruce's waistband, pulling them flush against each other again for a final kiss.

"Go," he says in a hoarse voice. "Before I fuck you in the hallway."

Bruce doesn't move, just bites at Tony's ear. "So, that's how it's gonna go?" he says. "Can't wait to get inside me?"

Tony slips a hand under Bruce's shirt, dragging blunt nails down the small of his back before answering.

"Mm-hm," he says. "And then I want you inside me. Or you can go first, I'm versatile. As long as it's me and you and a bed for days."

"Fuck, Tony," Bruce whimpers, pushing away again. "I need to go… take about ten cold showers and try to get some sleep."

Tony watches him go, before running to the bathroom for a few cold showers of his own.

.

.

Bruce misses breakfast the next morning in favor of sleeping in after a restless night. When he finally makes his way to Tony's workshop, the insecurity hits him all at once. What if Tony regrets what happened? What if it's too awkward now?

Tony, however, erases the doubts as quickly as they've come on, by pressing Bruce into a deep kiss before he even says hello.

"Hey," Tony greets him after they're done kissing.

"Morning," Bruce says, running a hand through his messy hair, blushing in delight.

"I solved the mystery," Tony says, getting right to the point.

"Of Rae's mother?" Bruce asks, glancing down at the baby in the play-pen he knows wasn't there yesterday.

"Mhm," Tony says, pulling up something on one of the big screens and tapping it for emphasis.

Bruce reads it silently, eyes going wide as he puts two and two together.

"God…" he says, trailing off for lack of anything better to say.

"It took some creative cross-searching on Jarvis' part," Tony says, "But Rae's DNA was in the system. It found both her parents."

"Her dad died in the mess with Loki," Bruce says, mostly to himself, looking at the screen sadly.

"And her mother died in childbirth," Tony adds. "That shouldn't even happen anymore."

"Then who…" Bruce asks, knowing Tony will understand.

Tony switches the images on the screen, pulling up a picture of a petite girl in her young teens.

"Her sister, I think. Eileen, age thirteen. It says that both girls were put in the foster system, but there's no record of either of them actually being placed in a home."

"She ran away," Bruce says. "She must have been so scared."

"Hey," Tony says, coming over to wrap his arms around Bruce's waist and look at him with wide, honest, eyes.

"We'll find her."

"And then what?" Bruce says, "You're going to suddenly adopt two kids and set up house with me and the Other Guy?"

Tony shrugs and smiles. "Yep, pretty much. Sounds good. You in?"

"You're impossible," Bruce says, "I know you said you want to keep Rae, but this? Tony, this is a big commitment. To them, to me, to yourself. Are you sure?"

"No," Tony says, "But I'm going to do it anyway. So, are you in or what?"

"Impossible," Bruce repeats, fondly.

"Improbable," Tony corrects, "Almost anything is possible."

Bruce just shakes his head and lets Tony press him into the table for some pg-rated fun. Little eyes are watching, after all.

.

.

**A Few Months Later:**

.

"Damn it, Clint!" Tony yells as he sees the arrow flying through the air and smash through a window. "I told you to stop teaching my daughter to use weapons!"

"Sorry, Tony!" Eileen calls out from somewhere Tony can't see.

"Just be careful!" he yells back, smiling as he sees Bruce walking towards him with Rae on his hip.

They settle on the grass beside him and Rae toddles over to Tony before falling into his lap.

"Da!" she says, proudly.

Tony grins widely at Bruce.

"I'm definitely her favorite," he teases.

"Yeah, yeah," Bruce says, pulling Tony to lean against him, resting between his legs.

"It's OK," Tony continues, "I bet you end up being Leenie's favorite."

"She's a great kid," Bruce says, "And the therapist is really impressed with her progress. I'm glad she's ours."

"You hear that, Rae?" Tony stage whispers, "Daddy Bruce is playing favorites, and you're losing!"

Bruce flicks Tony in the arm.

"I don't have a favorite," he says, "You're a menace."

"I do," Tony says, leaning back to rest his head on Bruce's shoulder and kiss his cheek.

"Who's your favorite, then?" Bruce asks, actually slightly worried that Tony would pick between the girls.

"Me, obviously," Tony says, and Bruce cracks up. "But," Tony continues, voice going softer, "You come a really close second. It's a photo finish."

Bruce lies back, pulling Tony and Rae with him, until they're sprawled out comfortably in the warm sun.

"You're impossible," he says, for what feels like the millionth time.

"Improbable," Tony corrects.

"Almost anything is possible," Bruce agrees.

He closes his eyes against the sun, listening to Rae's babble and Tony's laughter, and Eileen's delighted whooping somewhere in the background. It's a good day.

THE END.


End file.
